Bolt-anchor.



H. W. PLEISTER.

BOLT ANCHOR.

APPLICATION FILED }AH.20, `I`9l7. L @f-m mmm: Nov. 2?, 19N.

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HENRY W. PLEISTEB., 0F WESTFIELD, NEW JERSEY, ASSIGNOR T0 HENRY B.NEWIIALL.

BOLT-ANCEOR.

specification of Letters Patent. Patented Nov. 2*?, ist?.

Original application led September 20, 1916, Serial N o. 121,164.Divided and this application led January To all 'whom z' may concern:

Be it known that I, HENRY W. PLnrsTER, a citizen of the United States,residing at Westiield, in the county of Union and State of New Jersey,have invented certain new and useful Improvements in Bolt-Anchors, ofwhich the following is a specification, taken in connection with theaccompanying drawings.V Y

This application is a ,division of my copending application Ser. No.121,104 filed Sept. 20, 1916, for, improvements in bolt anchors.

My invention relates to bolt anchors.

In the present form of bolt anchors the maximum expansion isapproximately at the extreme inner end of the anchor'. In practice thisis often a serious detriment in that the screw or other expandingmember, having forced the bolt anchor out to its maximum expansion,binds and it is impossible to bring the head of the bolt or screw upflush with the work. This requires that the hole be enlarged entailingadditional labor and expense, or `that a different size bolt anchor beused.

By my invention I'overcome this serious objection and give a longersurface of maximum contacter grip on the exterior of the bolt anchor,thereby giving an increased frictional hold and distributing thismaximum grip over a larger area than with the present forms. Myinvention further permits the screw or bolt to coperate with the boltanchor With less efort, than in the present forms. r

My present invention relates to providing a bolt anchor with weakeningportions, in connection with the other features hereinafter set forthandto certain details of construction all of which will be described in thespecification and pointed out in the claims.

I have shown in the accompanying drawings several illustrativeembodiments of my invention but of course it is to be understood that myinvention is not to be confined simply to the forms illustrated exceptas required by the scope of the appended claims. In these drawings thesame reference numerals refer to the similar parts in the severalfigures. Y

Figure 1 is a verticalsection through a two part bolty anchor known as atwo part Serial No. 143,426.

lag shield, showing weakening portions, and having an axial bore, onepart of which is inclined reaching its maximum inclination between theends of the anchor and then merging into a substantially cylindricalbore, the weakening portions being preferably located adjacent to themaximum inclination of the inclined surface;

Fig. 2 is a vertical section through the two part lag shield of Fig. 1shown expanded by the lag screw holding the work to the support;

Fig. 3 is a vertical section of the two part lag shield showing amodified form of weakening portions formed by deepening one of thefemale screwthreads of the lag shield;

Fig. 4 is a vertical section of the two part lag shield showing adifferent manner of forming weakening portions by ruiming a hole oraperture through both parts of the lag shield;

Fig. 5 is a vertical section showing `the lag shield of Fig. 41 in itsexpanded position;

Fig. 6 is a transverse vertical section substantially on the line 6-6 ofFig. 4L;

Figi is a detail view of another modified form showing a two part lagshield having weakening valleys on its outside;

Fig. 8 is a longitudinal vertical section through a one part boltanchor, known as a one part lag shield, provided with my weakeningportions;

Fig. 9 is a vertical section through the one part lag shield shown inFig. 8, the support, and the work supported, showing the cooperating lagscrew in side elevation;

Fig. 10 is a side elevation, partly broken away, of a ductile anchorprovided with weakening portions; and

Fig. 11 is a vertical section of the ductile anchor of Fig. 10, expandedand coperating with a wood screw which is shown in side elevation.

In the illustrative embodiments of my invention, 1, Fig. l, is a lagshield form of two members 2 and 3 and provided with the usual clampinglugs et, as is the common practice, only one being shown in this figure.

In the form of lag shields now on the market, the axial bore has aninclined substantially uniform taper extending from near one end to theother end of the shield. In ooperating with the lag screw, such as 5,the maximum expansion, in the old form,

is approximately at a point equivalent to 6, 6. In my invention I form alag shield with an axial bore 7 having an open throat 8, aninclinedportion 9, which reaches its maximum'inclination at the points 10, 10,some distance from the end 11 of the lag shield. From the points 10, l0I form my axial bore with a substantially cylindrical surface 12, thesurface being substantially parallel to the longitudinal axis of thebolt anchor. By my invention, the maximum grip instead of beingconinedVat the end of the bolt anchor, as in the old form, is distributed alongthe surface of the bolt anchor 15 from points 13, 13 to the points G,(3, which distance of course may be varied. This gives along surface ofcontact and increased frictional` hold and insures the maximum grip overa larger area.

In use the lag shield 1 is mounted in ahole 14 in .a support v15, Fig.2, and the lag' screw 5'is then passed througl'i the work 16, throughthe open throat 8 along the inclined-l portion 9 and the cylindricalsurface 12 of the axial bore. is thev lag screw passes through the openthroat 8, there is nov expansive coperation between it and thel lagshield 1as it is desirable to have the expansion take place backfrom-the'face 17 of the support' 15. UponI reaching' the inclinedsurface 9, the expansion of the'lag shield begins and continuescomparatively sharply until the points 10, 10 of maximum inclination arepassed, when the expansion is uniform.

To permit the ready expansion of the lag shield 1, `I provide it withweakening portions 18, 18'in any suitable manner. In the form shown inFigs. 1 and 2, these 40 weakening'portions 18, 18 are formed by deepvalleys 19, 19 which are preferably cast in the parts 2 and 3 of thelag' shield when this shield is cast in the ordinary manner. Theseweakening portions 18', 18 permit the ends 20, 20 of the members 2 and3of the lag` shield to bend or springat these weakening portions whichare preferably located adjacent to the points 10, 10

0f the inclined surface 9, which points are the nearest approach to theaxis, and in that manner tend te closeup the valleys 19, 19 asshown inFig; 2. It will', therefore, be seen that as'the lag screw 5 travelshome the maximum expansion, instead of being' at the points6,16, as inthe old form, is distributed over' comparatively a large area of thewall 21 ofthe hole 1llying' between the points G, G-'and the points 13,13,-the weakening portions 18, 18, permitting the more ready insertionof the 'lag screw by permitting thebending of the parts 2 and. 3 atpoints adjacent to the maximum inclination of the inclined surface 9. Inthis' form the -malethreads22 of the lag screwA 5 co- 6b operate withthe female screwthreads 23 of the lag shield,vthese latterbeingpreferably cast in the sections 2 and 3 in the mold.

The same size lag shield and lagscrew will hold work of differentthicknesses 16 70 the same as more fully described in my said parentapplication, and in all cases the head of the lag screw or the woodscrew, the latter being' particularly used with the anchor shown! inFigs. 10 and 11, can be instantly 75 brought up flush against the workwhatever its thickness may-beiw-itlioutithe screw jamming in a positionwhere -its`-head cannotil be brought v up snugly against the work. Thisis due to the factl that the surface of maximum expansion is-extendedover ai relatively largeportion of the surface of the lag shield andanchor soi that the end of the screw can be"broughtanywhere along thecylindrical portion of the axial bore,-or pastthe end of thelag shieldor'anehor, as the-case-may be,-as may be found necessary to bring thehead`-of the'screw flush against the work and at the same timeobtain therequisite maximum expansion of 90 the lag shield or lead anchor." In theold form as previously noted, where the expansionis at'the end of theshield, the lag screw or wood screw would oftenjam at this point beforeitshead wasbroughtiiush with the work requiring the removal of the lagshield, or anchor?, andf the enlargenient of the hole, or the use off adifferent size lag shield or anchor. v Y 1 The weakening portions may beformed in my lag shields orleadanchors'in other numerous ways. vForpurposes of illus! tion I- have shown a few different ways of providing'the weakening portions-ibut .of course it is to be understood, thatmyfinvention is not to be limitedV to `these particu-- lar forms, which areshown simply by way of example.

In Fig. 3 VI have shownV a belt anchor 24 formed of' sections 25 and 26,the weaken- 110 ing' portions 27,127` being formed bydeepening' one ofthe female screwthreads28, the other female screw'threads 29, 29 being"of the ordinary depth.

I may in some instances provide a boltL anchor 30, Figs. 41, 5"and6,-witlrweakening' portionsv 31, 31 formed; by making" a.- hole or slot32 directly through the two portions' 33, 33 of the bolt anchor. InFig'. 5 I-have shown thebolt anchor of Figi located in a wall andsupportingthework, itsl action being the same as thatpreviouslydescribed.

In some instances I may place valleys34, 34k, Fig. 7, in the parts 35and 36 of the lagf shield 37 formingweakening portions`38,`38`. 125

I may also employ weakening' portions, preferably `located adjacentv thepoint' of nearest approach to the axis of theinc'lined surface of a onepart lag'4 shieldlas shown for example in F igsS and 9.`

igiene? ln these figures the lag shield 39 is provided with an openthroat 40 and with an. inclined surface 4l reaching its maximuminclination at the point 42, and there merging into a parallel orsemi-cylindrical surface 43. The lag shield is preferably provided withthe female screw-threads 44 and also preferably with one or more lugs45, 45. The weakening portion 46 is formed by casting a valley 47,which, as previously noted, for best results, should be located adjacentthe point 42 of the inclined surface 4l, the nearest approach to theaxis. In this form the lag screw 48 coperates with the inclined surface4l and the semi-cylindrical surface 43 and also with that portion 49 ofthe wall of the hole 50 in the support 5l which is not covered by thelag shield 39. In this form the work 52 is held to the face 53 of thesupport, the same as in the other forms, the weakening portions 46permitting the end 54 to bend with relation to the other portion of thelag shield which permits the more ready insertion of the lag screw inthat the force required to bend the metal of the lag shield is verylargely dispensed with.

Ductile anchors, screw anchors, or ancho-rs, as they are known in thetrade, may also be made in accordance with my invention.

ln Figs. l0 and l1, l have shown an anchor 55 provided with the inclinedsurface 56, the cylindrical surface 57 and the weakening portions 58formed by the exterior valleys 59, 59 which are located adjacent to thepoints of maximum inclination 60 of the inclined portion 56.

In these anchors the wood screw 6l supports the work 62 by passingthrough the collar 63 of the anchor 64 and expanding its two tines 65and 66 by cutting its own threads in the inclined portion 56 and thecylindrical portion 57 of the axial bore 67. ln this operation theweakening portions 58 give and permit the valleys 59, 59 to openslightly. Of course, it is to be understood that my invention may beused with a lag shield or lead anchor of any exterior configuration.

The walls of my bolt anchor are thinnest near one end and uniformlyincrease in thickness to a point intermediate the ends of the anchor,and from that point the walls continue with a. substantially uniformthickness to the other end of the anchor'.

One portion of the axial bore is in the form of a frustum of a conewhose base is near the entrance of the shield, its other end merginginto substantially a true cylinder at a point located between the twoends of the shield.

It will be seen that when the expanding means eoperate with the axialbore, said bore is distorted into a substantially true cylindrical borethereby distorting the forward exterior cylindrical surface of the boltanchor into a frustum of a cone, which merges into the cylindricalexterior of the outer end of the bolt anchor.

ln the different figures of the drawings, for purpose of illustration, lhave somewhat exaggerated the preferred angle of the inclined portion ofthe axial bore.

Having thus described this invention in connection with severalillustrative embodiments thereof, to the details of which l do notdesire to be limited, what is claimed as new and what is desired tosecure by Letters Patent is set forth in lthe appended claims.

l. ln a. bolt anchor an expansible member having an internal cavity, thesurface of said cavity being tapered for part of its length,

the other portion of the cavity being substantially cylindrical andprovided with a weakening portion adjacent to the point where thetapered and cylindrical surfaces meet.

2. In a bolt anchor an expansible member having an internal cavity, thesurface of said cavity being inclined with a uniform inward taper forpart of its length, said inclination ceasing at a point between the endsof the anchor and continuing and merging into a cylindrical orifice tothe farther extremity, said bolt anchor being provided with a weakeningportion located adjacent to the point where the inclined interiorsurface merges into the cylindrical surface.

3. ln ay bolt anchor expansible members forming on their exteriorsubstantially a cylinder and forming on their interior a bore coaxialwith the anchor, said bore tapering to a smaller diameter as itapproaches a point between extremities and from thence continuing withuniform diameter for the remainder of its surface to the oppositeextremity, one or more of said expansible members being provided with aweakening portion.

4. ln a bolt anchor, the combination of a plurality of expansiblemembers comprising a hollow cylindrical shield screw-threaded upon itsinner surface, said screw threaded surface being in the form of afrustum of a cone, whose base is near the entrance of the shield, theother end of the frustuin of a cone merging into a true cylinder at apoint located between the ends of the bolt anchor, and weakeningsections provided adjacent said merging points, and a rotatableexpanding member adapted to engage the screw-threaded interior surface.

HENRY W. PLEISTER. ll/iitnesses M. R. RYAN, A. M. WILLIAMS.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C."

